MimeMessageSource


1   /***********************************************************************
2    * Copyright (c) 2000-2004 The Apache Software Foundation.             *
3    * All rights reserved.                                                *
4    * ------------------------------------------------------------------- *
5    * Licensed under the Apache License, Version 2.0 (the "License"); you *
6    * may not use this file except in compliance with the License. You    *
7    * may obtain a copy of the License at:                                *
8    *                                                                     *
9    *     http://www.apache.org/licenses/LICENSE-2.0                      *
10   *                                                                     *
11   * Unless required by applicable law or agreed to in writing, software *
12   * distributed under the License is distributed on an "AS IS" BASIS,   *
13   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or     *
14   * implied.  See the License for the specific language governing       *
15   * permissions and limitations under the License.                      *
16   ***********************************************************************/
17  
18  package org.apache.james.core;
19  
20  import java.io.IOException  ;
21  import java.io.InputStream  ;
22  
23  /**
24   * This defines a reusable datasource that can supply an input stream with
25   * MimeMessage data.  This allows a MimeMessageWrapper or other classes to
26   * grab the underlying data.
27   *
28   * @see MimeMessageWrapper
29   */
30  public abstract class MimeMessageSource {
31      /**
32       * Returns a unique String ID that represents the location from where 
33       * this file is loaded.  This will be used to identify where the data 
34       * is, primarily to avoid situations where this data would get overwritten.
35       *
36       * @return the String ID
37       */
38      public abstract String   getSourceId();
39  
40      /**
41       * Get an input stream to retrieve the data stored in the datasource
42       *
43       * @return a <code>InputStream</code> containing the data
44       *
45       * @throws IOException if an error occurs while generating the
46       *                     InputStream
47       */
48      public abstract InputStream   getInputStream() throws IOException  ;
49  
50      /**
51       * Return the size of all the data.
52       * Default implementation... others can override to do this much faster
53       *
54       * @return the size of the data represented by this source
55       * @throws IOException if an error is encountered while computing the message size
56       */
57      public long getMessageSize() throws IOException   {
58          int size = 0;
59          InputStream   in = null;
60          try {
61              in = getInputStream();
62              int read = 0;
63              byte[] data = new byte[1024];
64              while ((read = in.read(data)) > 0) {
65                  size += read;
66              }
67          } finally {
68              try {
69                  if (in != null) {
70                      in.close();
71                  }
72              } catch (IOException   ioe) {
73                  // Exception ignored because logging is
74                  // unavailable
75              }
76          }
77          return size;
78      }
79  
80  }
81
A to Z: JavaDoc & Examples Daily Java News & Articles Open Source Projects Open Source Codes Free Computer Books Remove Frame
Popular Tags